Guile-hoot/lib/hoot/procedures.scm

;;; Procedures on procedures
;;; Copyright (C) 2023, 2024 Igalia, S.L.
;;; Copyright (C) 2023 Robin Templeton <robin@spritely.institute>
;;;
;;; Licensed under the Apache License, Version 2.0 (the "License");
;;; you may not use this file except in compliance with the License.
;;; You may obtain a copy of the License at
;;;
;;;    http://www.apache.org/licenses/LICENSE-2.0
;;;
;;; Unless required by applicable law or agreed to in writing, software
;;; distributed under the License is distributed on an "AS IS" BASIS,
;;; WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
;;; See the License for the specific language governing permissions and
;;; limitations under the License.

;;; Commentary:
;;;
;;; procedure?
;;;
;;; Code:

(library (hoot procedures)
  (export procedure? procedure-name)
  (import (only (hoot primitives)
                %eq?
                %procedure?
                %struct?
                %struct-vtable
                %vector-length
                %vector-ref)
          (hoot cond-expand)
          (hoot errors)
          (hoot inline-wasm)
          (hoot syntax))

  (define (procedure? x)
    (or (%procedure? x)
        ;; Can't call applicable-struct? here as it would create a
        ;; module cycle.
        (and (%struct? x)
             (let ((parents (%inline-wasm
                             '(func (param $vtable (ref $vtable))
                                    (result (ref eq))
                                    (call $vtable-parents (local.get $vtable)))
                             (%struct-vtable x))))
               (if (%eq? (%vector-length parents) 0)
                   #f
                   (%eq? (%inline-wasm
                          '(func (result (ref eq))
                                 (global.get $applicable-struct-vtable)))
                         (%vector-ref parents 0)))))))

  (cond-expand
   (guile-vm
    (define (procedure-name proc)
      (check-type proc procedure? 'procedure-name)
      #f))
   (hoot
    (define (procedure-name proc)
      (check-type proc procedure? 'procedure-name)
      (%inline-wasm
       '(func (param $proc (ref $proc)) (result (ref eq))
              (local $maybe-string (ref null string))
              (call $code-name (struct.get $proc $func (local.get $proc)))
              (local.set $maybe-string)
              (if (ref eq)
                  (ref.is_null (local.get $maybe-string))
                  (then (ref.i31 (i32.const 1)))
                  (else (struct.new $string (i32.const 0)
                                    (ref.as_non_null (local.get $maybe-string))))))
       proc)))))